Class Anthozoa is a group of marine invertebrates that are commonly known as corals. They are characterized by their flower-like appearance and are primarily sessile, meaning they are attached to the ocean floor. Anthozoa is a diverse group, containing over 6,000 species and several different sub-classes and orders. Synonyms for Anthozoa include flower animals, sea anemones, and stony corals. Although these synonyms are not always interchangeable, they do all refer to different members of the Anthozoa class. One thing that these synonyms have in common is their importance to the ocean ecosystem, both as key components of marine biodiversity and as crucial reef-building organisms.